PROBLEM: Is there a way I can remove Classic from my OS X system? I don't have system 9.x installed, but the Classic pane is still in my System Preferences.

SOLUTION: When people say they want to "uninstall" Classic, what they may mean is that they want to disable the System Preferences "Classic" pane. If you don't have an OS 9 install at all, or OS X is installed on a UFS partition, Classic won't start up anyway. Simply remove the /System -> Library -> PreferencePanes -> Classic.prefPane file, and that's the last you'll see of Classic again. You'll need to have root-level privileges to do this, of course.

[robg adds: As a caution, you may want to think twice before doing this -- the possible implications on future Software Updates that may try to update Classic resources is, of course, not known. More than likely, the updater would just install entire components, but personally, I prefer to leave as much of my system in 'stock' mode as possible to minimize potential upgrade difficulties. That warning aside, read the rest of the hint for info on how to remove the rest of Classic support from your machine...]

If you want to remove the whole Classic support structure from your system, you'll want to remove the Classic files and directories created by the OS X installer:

In addition to this, if you've already run Classic and would like to remove it afterwards, you'll want to remove any of these additional files and directories that exist in the root of the OS X installation:

A lot of Mac OS X users think that by removing OS 9 they are
going to improve the performance of their system, but this
simply isn't true. If its unused, there is no performance loss.

Its best to keep OS 9 around "just in case" - you don't want to
have to install OS 9 just to run some one-time-only app. Also, is
can be easier to run some diagnostics from OS 9. I spent a bit
of time explaining this to customers, but it seems a lot of
people have a hard time understanding this.

Could one create -- and to add irony upon irony, maybe do
this while in OS 9 -- SystemPreferences (Disabled) within
the Library folder, then drag in Classic,prefPane? Then you
could at least put the Pane back where it was and reboot if
all goes poorly (even if you have to boot from an OS 9 CD).

Also, does dragging Network.prefPane out of
SystemPreferences eliminate the Network Startup icon
within the Startup panel? That could be another big plus
for some of us in the support arena.

I cannot stress this enough: DO NOT TOUCH /System/Library.
You can add things to /Library or preferably to ~/Library (if only
your user needs it), but there is never a good reason to mess
with /System/Library. Leave it alone.

That is very true - if somebody wants to get rid of things you don't use, turn to the help files. A file-counting program I ran found out that on my computer, html files were by far the most common. Go hunt for those or something...